My brothers 7 1/2 year dog is scratching his back and tail and he’s literally bald on the back, and has raw skin showing cause he scratches his skin so much with his teeth, he has these skin growths on his tail to that look like skin cancer or some keloid. I noticed one week ago that his back legs are very weak, and he dragged his legs like he couldn’t use them, he rolls on the porch all day to scratch his rough bald back. i looked on google and it says he could have degenerative myelopathy, it affects the muscles in the back legs. It happens usually in older dogs. I told my brother that sooner or later he’ll have to put down his dog and he’s wondering when he should?